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#include <iostream> template<typename T> class Stack { public: Stack() : top(nullptr) {} ~Stack() { while (!isEmpty()) { pop(); } } void push(const T& value) { Node* newNode = new Node(value); newNode->next = top; top = newNode; std::cout << value << " pushed to stack" << std::endl; } void pop() { if (isEmpty()) { std::cout << "Stack is empty. Nothing to pop." << std::endl; return; } Node* temp = top; top = top->next; std::cout << temp->data << " popped from stack" << std::endl; delete temp; } T peek() const { if (isEmpty()) { throw std::runtime_error("Stack is empty."); } return top->data; } bool isEmpty() const { return top == nullptr; } void display() const { Node* current = top; if (isEmpty()) { std::cout << "Stack is empty." << std::endl; return; } std::cout << "Stack elements:" << std::endl; while (current != nullptr) { std::cout << current->data << std::endl; current = current->next; } } private: struct Node { T data; Node* next; Node(const T& value) : data(value), next(nullptr) {} }; Node* top; }; int main() { Stack<int> stack; stack.push(10); stack.push(20); stack.push(30); std::cout << "Top element is: " << stack.peek() << std::endl; stack.display(); stack.pop(); stack.pop(); std::cout << "Top element is: " << stack.peek() << std::endl; stack.display(); return 0; } |
Explanation:
- Stack Class:
- Attributes:
top: Pointer to the top node in the stack.
- Nested
NodeStructure:data: Stores the value of the node.next: Pointer to the next node in the stack.
- Methods:
Stack(): Constructor initializes an empty stack.~Stack(): Destructor deletes all nodes to free memory.push(const T& value): Adds a new element to the top of the stack.pop(): Removes the top element of the stack. If the stack is empty, it prints a message.peek() const: Returns the top element of the stack without removing it. Throws an exception if the stack is empty.isEmpty() const: Checks if the stack is empty.display() const: Displays all elements in the stack from top to bottom.
- Attributes:
- main Function:
- Demonstrates the usage of the
Stackclass. - Performs operations such as pushing elements, displaying the stack, popping elements, and checking the top element.
Compilation:
To compile the program, use:
Run the program with:1g++ stack.cpp -o stack
1./stack
- Demonstrates the usage of the